After making a heroic stand and holding McClellan and his overwhelming force at bay for nearly a month, Magruder abandoned his lines and fell back to Williamsburgh on the road up the Peninsula to Richmond. He was slowly followed by McClellan's army. Smith's division having crossed the Warwick at Lee's mill, led in the pursuit, coming up with the enemy strongly posted in a new line of fortifications covering the town of Williamsburg. Smith's engineering skill and his quick intelligence served him again most fortunately, and with the aid of Captain West of the Coast Survey then serving on his staff, soon enabled him to find the weak spot in the enemy's position. This time it turned out to be on the extreme left, where he had failed, probably through lack of troops, to occupy the extensive works which had been previously constructed. Realizing intuitively the futility of a front attack against such entrenchments, Smith threw Hancock's brigade promptly to the right and under cover of the woods, succeeded without serious loss or delay in occupying one of the works from which, with his division he could easily have swept the whole line had he not been restrained by the presence of his seniors. Unfortunately McClellan was in the rear, but Sumner and Heintzelman, corps commanders, were soon upon the ground, and with prudent but ill-timed conservatism declined to sanction the proper movement to reinforce Hancock, for fear that it would bring on a general engagement before the army could be properly closed up and placed in position to participate. Smith recognizing, the great advantage certain to arise from pushing promptly through the opening he had already found, besought Sumner for permission to go with the rest of his division to Hancock's assistance, but this was also denied. As other troops arrived on the field, Smith moved to the right to make place for them, with the hope that he might be permitted to continue his march unobserved till he had come up with his advanced brigade, but orders were sent which arrested him before he had accomplished the object he had in view. All day long he was held in the leash with certain victory in sight. McClellan arrived on the field late in the afternoon, but before he could get a satisfactory understanding of the condition of affairs, night came on. Consequently nothing decisive was done that day and a great opportunity was lost. The wily Magruder, seeing that his left had been turned, and that his position was untenable, abandoned his works under cover of darkness and fell back towards Richmond. Obviously this result was due, first, to the fortunate discovery made by General Smith and his engineer, and to the successful turning movement of Hancock, based thereon; and, second, to the certainty that if properly reinforced by the rest of Smith's division, and by other divisions, if necessary, as it surely would be as soon as the national commander had